Haloaryloxyalkyl esters of alpha, alpha-dichlorobutyric acid



HALOARYLOXYALKYL ESTERS OF oc,oc-=DICHLOROBUTYRIC ACED Herman 0. Senkbeil, Charles T. Pumpelly, and Harry F. Brust, Midland, Mich., assignors to The Dow Chemical Company, Midland, Mich., a corporation of Delaware No Drawing. Application July 2, 1956 Serial No. 595,070 g 6 Claims. (Cl. 260-487) This invention relates to the haloaryloxyalkyl esters of -dichlorobutyric acid. These compounds are crystalline solids or viscous liquids somewhat soluble in many organic solvents and only slightly soluble in water. They have been found to be active as plant growth control materials and soil sterilants and are adapted to be employed as active toxic constituents in dust and liquid compositions for the control of the growth and the killing of weeds and for the sterilization of soil with regard to the growth of plants. The compounds are also useful as parasiticides for the control of many insect and bacterial organisms such as Rhizoctonia solani.

The compounds may be prepared by reacting apt-dichlorobutyric acid with a haloaryloxyloweralkanol. The reaction may becarried out in the presence of an esterification catalyst such as sulfuric acid, phenol sulfonic acid or a cation exchange resin in the acid form, and conveni- .ently in a water-immiscible solvent such as ethylene dichloride, monochlorobenzene or toluene. The amount of reactants employed is not critical since some of the desired ester product is produced with any proportion of reagents. However, good results are obtained when substantially equimolecular proportions of the reactants are employed. The employment of an excess of the alkanol coupled with the continuous removal of the water of reaction as formed generally results in optimum yields.

In carrying out the reaction, the a,a-dichlorobutyric acid, haloaryloxyalkanol and catalyst, if employed, are mixed andthe resulting mixture heated at a temperature of from 75 to 180 C. for a sufficient period of time to complete the reaction. In an alternative procedure, the reactants and catalyst, if employed, are dispersed in the solvent and the resulting mixture heated at the boiling temperature. During the heating period, the water of reaction and some of the solvent are continuously removed by distillation, condensed and the solvent recovered. More solvent may be added to the reaction mixture if necessary. 7

Upon completion of the reaction, the desired product may be separated by fractional distillation under reduced pressure. If the product is a solid and precipitates from the cooled reaction mixture before or after removal of the reaction solvent, it may be separated by filtration and purified by recrystallization from various organic solvents. In another method of separation, the solventmixture of the reaction product is neutralized with an alkali such as dilute aqueous sodium carbonate. The reaction mixture divides into aqueous and solvent layers which may be separated by decantation. The solvent layer containing the ester reaction product is washed several times with water and then fractionally distilled under reduced pressure to obtain the desired ester compound.

The following examples illustrate the invention but are not to be construed as limitations thereof:

United States PatentO was recrystallized Example 1.-2-(2,4,5-trichlorophenoxy)-ethyl a,a-dichlorobutyrate 130.75 grams phenoxy)-ethanol (melting (0.54 mole) of 2-(2,4,5-trichloroat 66.5-68.5 C.) and 93.5

grams (0.60 mole) of a,a-dichlorobutyric acid were water and fractionally distilled under reduced pressure to separate a 2-(2,4,5-trichlorophenoxy)-ethyl e u-dichlorobutyrate product boiling at 152-153 C. at 1 millimeter pressure. This product crystallized upon cooling and from ethanol. The recrystallized product melted at 62-63 C. and had a chlorine content of 45.4- percentas compared to a theoretical content of 46.6 percent.

Example 2.-2-(2,4,5-trichl0rophenoxy)-1-pr0pyl a,a-dichlor0butyrate l CH: 0 C1 chlorobutyric acid and 0.5 milliliter of concentrated sulfuric acid was dispersed in 200 milliliters of ethylene dichloride. The resulting mixture was heated for 17 hours at a temperature of C. while the water of reaction was continuously distilled along with some of the ethylene dichloride from the reaction zone. Upon completion of the reaction, the mixture was washed with water and partially distilled under reduced pressure to remove the ethylene dichloride. There was obtained as a viscous liquid residue a 2-(2,4,5-trichlorophenoxy)-1-propyl mp1- dichlorobutyrate product having a saponification equivalent of400 and a chlorine content of 44.8 percent as compared to the theoretical value of 44.9 percent.

Example 3 .2-(3,4-d ichl0r0phen0xy -ethyl a,a-dichlorobutyrate 87 grams (0.55 mole) of or,oz-dich'lorobutyric acid, 104 grams (0.5 mole) of -2-(3,4-dichlorophenoxy)-ethanol (having a refractive index n/D of 1.5494at 25 C.) and 0.5 milliliter of concentrated sulfuric acid were dispersed in 200 milliliters of ethylene dichloride and the resulting mixture heated for 20 hours at the boiling temperature. The heating was carried out in the usual fashion with continuous distillation of some of theethylene'dichloride and water of reaction was formed. Upon completion of the reaction,.the reaction mixture waswashed withwaterancl the ethylene dichloride removed by distillation at atmospheric pressure. The residue was thereafter fractionally distilled under reduced pressure to separate a 2- (3,4-dichlorophenoxy)-ethyl a,u-dichlorobutyrate product as a viscous liquid boiling at 140l43 C. at 0.5 millimeter pressure and having a chlorine content of 40.3 percent as compared to the calculated ,value of 41.0 percent.

Example 4.] -(3,4-dich lorophenoxy -2-pyropyl A mixture of 44.2 grams (0.2 mole) of l-(3,4-dich1orophenoxy)-2-propanol (having a molecularv weight of 233) and 34.5 grams (O.22 mole) of a,a-dichlorobutyric acid was dispersed in 150 milliliters of ethylene dichloride 146-150 C. at 0.1 millimeter pressure.

Example 5.2-(4-chlor0-2-methylphen0xy)-ethyl a,a-dichlorobutyrate CHs One mole of 2-(4-chloro-2-methylphenoxy)-ethanol (melting at 5155 C.), one mole of 0:,zx-diCh1OlOblltYllC acid and l milliliter of phenol sulfonic acid are dissolved in 400 milliliters of ethylene dichloride and the resulting mixture heated at the boiling temperature for 20 hours. The reaction mixture is then fractionally distilled under reduced pressure to separate the desired ester product as a viscous liquid having a molecular weight of 330.

Example 6.1-(pentachlorophenoxy)-2-pr0pyl u,oz-dichl0r0butyrate A mixture containing one mole quantities of (pentachlorophenoxy)-2-propanol (melting at 6466 C.) and a,a-dichlorobutyric acid and 1 milliliter of sulfuric acid in 150 milliliters of ethylene dichloride is heated for 22 hours in the usual manner while continuously removing a mixture of ethylene dichloride and water of reaction as formed. The reaction mixture is then fractionally distilled to separate the desired ester product which has a molecular weight of 400.

7.2-(4-brbmophenoxy)-ethyl a,a-dichlorobutyrate 0 0.75 mole of 2-(4-bromophenoxy)-ethanol (melting at 5155 C.) and 0.78 mole of a,a-dichlorobutyric acid are dispersed in 200 milliliters of ethylene dichloride and the resulting mixture heated'at about 110 C. for 50 Example hours. 'The heating is carried out with continuous distillation of the water of reaction and entraining agent as previously described. Following the heating period, the mixture is washed with water and fractionally distilled under reduced pressure to separate a 2-(4-bromo phenoxy)-ethyl a,a-dichlorobutyrate product having a molecular weight of 290. I

In a similar manner, other haloaryloxyalkyl 0:,a-diChlO- robutyrates may be prepared as follows:

2 (2 bromo-4-chlorophenoxy)-ethyl a,oz-diChlOl'Obutyrate by the reaction of 0:,a-CliChl0I0blltYliC acid and 2- (2-bromo-4-chlorophenoxy)-ethanol.

2 (2,4 dibromophenoxy)-ethyl 0:,tz-diChl0l0bHtYI3t6 by the reaction of a,a-dichlorobutyric acid and 2-(2,4- dibrcmophenoxy)-ethanol.

2-(4-chlorophenoxy)-ethyl a,a-dichlorobutyrate by the reaction of a,a-dichlorobutyric acid and 2-(4-chlorophenoxy)-ethanol.

3 (2,4-dichlorophenoxy)-l-butyl a,a-dichlorobutyrate by the reaction of a,a-dichlorobutyric acid and 3-(2,4-dichloro"henoxy)-l-butanol.

3-(4-chlorophenoxy)-l-propyl a,a-dichlorobutyrate by the reaction of 0:,ot-diChlOlOblJtYIiC acid and 3-(4-chlorophenoxy)-l-propanol.

The new a,a-dichlorobutyric acid esters are useful as parasiticides and herbicides and are particularly valuable for the eradication of grasses such as Johnson grass and Canary grass. The compounds are very persistent in soil and are adapted to be employed to control the growth of seed emerging seedlings and established plants over a prolonged period of time. For such use the products may be dispersed on an inert finely divided solid and employed as dusts. They may also be dispersed in water with the aid of a wetting agent and the resulting mixture employed as a spray. If desired, the products may be employed as constituents of oil-in-water emulsions or water dispersions with or without the addition of surface active agents. In representative operations, percent controls of Canary grass have been obtained with foliar applications of aqueous compositions containing 500 parts by weight of 2-(2,4,5-trichlorophenoxy)-l-propyl 0:,zx-dlChlOI0blltYlfitfi per million parts by weight of ultimate mixture.

The haloaryloxyalkanols employed as starting materials are conveniently prepared by reacting an alkali metal salt of an appropriate phenol with a monohaloaliphatic alcohol such as ethylene chlorohydrin, propylene chlorohydrin, 2-chloro-1-propanol, 3-bromo-l-propanol, 3-chloro-1-propanol, 3-chloro-2-propanol and 3-chloro-1- butanol.

We claim:

1. An a,n-dichlorobutyrate of a haloaryloxyloweralkanol selected from the group consisting of bromophenoxyloweralkanols, bromotolyloxyloweralkanols, chlorophenoxyloweralkanols and chlorotolyloxyloweralkanols.

'2. An a,a-dichlorobutyrate of a haloaryloxyethanol selected from the group consisting of bromophenoxyethanol, bromotolyloxyethanol, chlorophenoxyethanol and chlorotolyloxyethanol.

3. 2 (2,4,5 7 trichlorophenoxy) -ethyl oz,oc-diCl1l0r0blltyrate.

' 4. 2-(2,4,5-trichlorophenoxy)-1-propyl 0:,cc-diChl0l'ObU- tyrate.

5. '2-(3,4-dichlorophenoxy)-ethyl a,a-dichlorobutyrate.

6. 1 (3,4-dichlorophenoxy)-2-propyl a,u-dichlorobutyrate.

References Cited in the file of this patent UNITED STATES PATENTS 2,693,407

2,765,224 Lambrech Oct. 2, 1956 

1. AN A,A-DICHLOROBUTYRATE OF A HALOARYLOXYLOWERALKANOL SELECTED FROM THE GROUP CONSISTING OF BROMOPHENOXYLOWERALKANOLS, BROMOTOLYLOXYLOWEERALKANOLS, CHLOROPHENOXYLOWERALKANOLS AND CHLOROTOLYLOXYLOWERALKANOLS. 